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U. S. DEPARTMENT OF AGRICULTURE. 



SB 201 

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Xopy 2 



BUREAU OF PLANT INDUSTRY- -BULLETIN NO. 90, PART I. 

B. T. GALLOWAY, Chief of Bureau. 



THE STORAGE AND GERMINATION OF 
WILD RICE SEED. 



J. W. T. DUVEL. 

•i 

Assistant in the Seed Laboratory. 



Issued Septembeb 7, 1905. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 
19 5. 

ionograjrtr 



UN 8 1907 
1M D.ofD. 



CONTENTS. 



Page. 

Introduction - 5 

Distribution 5 

Habitat 6 

Germination of the seed 7 

Fall seeding versus spring seeding 7 

Directions for storing the seed - 8 

Detailed conditions and results of storage experiments - 9 

Packing for transportation 11 

Methods of making germination tests 11 

Effect of temperature on germination 12 

Summary 12 

Description of plates 16 

3 



ILLUSTRATIONS. 



Page. 
Plate I. Wild rice growing in water after being kept wet in cold storage at a 
temperature of 32-34° F., from October 19, 1903, to November 15, 

1904 16 

II. Stages of germination of wild rice, showing the development of the 
root system and the relative position of the seedling and the parent 

seed 16 

4 



B. P. I. — 17? 



THE STORAGE AND GERMINATION OF WILD 

RICE SEED." 



INTRODUCTION. 

The seed of wild- rice, sometimes called Indian rice or water oats 
(Zizania aquatica L.), has alwaj r s been a very valuable food among 
the Indians, especially those of the upper Mississippi Valley. Of 
recent years wild rice has found a place on the menu cards of some 
of our best American hotels. The rich and highly nutritious grains, 
together with the slightly smoky flavor it has when properh T pre- 
pared, make it an extremely palatable article of diet. If it were not 
for the difficulties of harvesting the seed and preparing the finished 
product for market it is probable that wild rice would find a place in 
many American homes. 

At present, however, the greatest interest in wild rice is created by 
the value of the seed as a food for wild waterfowl, particularly wild 
ducks. As a result of this interest the propagation of wild rice from 
seed has become a question of considerable importance, especially to 
the members of the gunning clubs throughout the United States and 
Canada. 

DISTRIBUTION. 

The distribution of wild rice is now reported from New Brunswick 
and Assiniboia south to Florida, Louisiana, and Texas. There are. 
however, comparatively few localities in which it grows abundantly. 

« Wild rice is considered one of the most important foods for wild ducks and other 
waterfowl, and a large number of inquiries have been received from members of 
gunning clubs throughout the United States asking where good, germinable seed can 
be secured. It is quite generally recognized that wild rice seed loses its vitality if 
allowed to become dry, and better methods of storing the seed during the winter 
have long since been demanded. 

The results of investigations begun two years ago show that wild rice seed can be 
handled without any deterioration in vitality if it is harvested and stored according 
to methods outlined in the present paper. 

J. W. T. Duvel, Acting Botanist in Charge of Seed Laboratory. 
Seed Laboratory, 

Washington, D. C, July 20, 1905. 

5 



6 STORAGE AND GERMINATION OF WILD RICE SEED. 

Good reasons exist for assuming that this area can be extended to 
include all fresh-water lakes, as well as swamps and river bogs, where 
the water does not become stagnant, throughout the whole of North 
America south of latitude 55° north. Wild rice also grows luxuri- 
antly along the lower parts of many of the rivers of the Atlantic Coast 
States, the waters of which are affected by the action of the tide to a 
considerable degree, and consequently contain an appreciable quantity 
of salt. It has been shown a that the maximum degree of concentra- 
tion of salt water in which wild rice plants can grow successfully is 
equivalent to a 0.03 normal solution of sodium chlorid. This concen- 
tration corresponds to 0.1755 per cent by weight of sodium chlorid, 
which is sufficient to give a slight salty taste to the water. 

HABITAT. 

While it is well recognized that the habitat of the wild rice plant is 
in shallow fresh water, it is now known that it will grow luxuriantly 
in water containing little less than two-tenths of 1 per cent of sodium 
chlorid. Occasional plants have been found growing in water which 
contained, for short periods at least, nearly double that amount of 
salt. These facts indicate the possibility of a much wider range of 
conditions to which this plant ma}^ be subjected without hindering its 
development. It is not beyond the range of possibility — indeed, it is 
quite probable — that by careful selection plants may be obtained which 
will thrive on soil that is comparatively diw, at least in places in which 
the water can be drawn off gradually during the latter part of the 
growing season. 

In September, 1904, Mr. G. C. Worthen, of the Bureau of Plant 
Industry, collected a cluster of wild rice plants which were growing 
on the Potomac Flats, near Washington, D. C, in soil which was suf- 
ficiently dry to permit the use of a 2-horse mowing machine for cutting 
down the rank growth of vegetation. This was newty made land, and 
in all probability the seed giving ' rise to this cluster of plants was 
pumped in with the dirt from the Potomac River the year previous. 

This amphibious t} T pe once established, it will undoubtedly carry 
with it a strain of seed which can withstand considerable drying with- 
out any marked injury to its vitalit}^. Such being true, the methods 
and difficulties of propagation from seed would be greatly simplified. 

Simultaneous with establishing an amphibious type should come the 
selection of seed plants which are capable of retaining their seed until 
the larger part of it has reached maturity. These two steps once 
made, the future of wild rice as a cereal will be assured. 

a The Salt Water Limits of Wild Rice. Bulletin No. 72, Part II, Bureau of Plant 
Industry, United States Department of Agriculture, 1905. 



FALL SEEDING VERSUS SPRING SEEDING. 7 

GERMINATION OF THE SEED. 

The greatest difficulty to be overcome in extending the area for 
growing wild rice is the poor germination of the commercial seed. 
Inasmuch as wild rice constitutes one of the most important foods of 
wild ducks and other wild waterfowl, many individuals and most of 
the gunning clubs east of the Rocky Mountains have been asking the 
question, How can we propagate wild rice from seed in order to estab- 
lish better feeding and fattening grounds for our game birds ( 

The many failures in the propagation of wild rice from seed have 
been due to the use of seed that had become dry before sowing, or to 
the fact that the seed when sown fresh in the autumn had been eaten 
by ducks or other animals or was carried away by heav} r floods before 
germination took place. 

It is now very generally known that the seed of wild rice, if once 
allowed to become dry, will not germinate, save possibly an occasional 
grain. In its natural habitat the seed, as soon as mature, falls into the 
water and sinks into the mud beneath, where it remains during the 
winter months, germinating the following spring if conditions are 
favorable. 

Heretofore the plan generally followed, and the one usually recom- 
mended by those who have given some attention to the propagation of 
wild rice, was practically that of natural seeding; that is, to gather the 
seed in the autumn, as soon as thoroughly mature, and, while still fresh, 
to sow it in 1 to 3 feet of water. 

FALL SEEDING VERSUS SPRING SEEDING. 

It must be remembered that the bulk of the seed remains dormant 
during the winter, germinating first the spring after maturing; con- 
sequently, with but few exceptions, fall seeding is unsatisfactory and 
unreliable. Fall seeding is likely to prove a failure for three reasons: 
(1) Wild ducks and other animals of various kinds eat or destroy the 
seed in considerable quantity before it has had time to germinate the 
following spring; (2) much of the seed is frequently covered so deeply 
with mud that washes in from the shore during the winter that the 
young plants die of suffocation and starvation before they reach the 
surface; (3) in some cases a large quantity of the seed is carried away 
from the place where sown by the high waters and floating ice prev- 
alent during the latter part of the winter and early spring. 

In exceptional cases these difficulties can be overcome; under which 
circumstances autumn sowing may be preferable to spring sowing. 
In the majority of cases, however, much better results will be 
obtained if the seed is properly stored and sown in the early spring, 
as soon as the danger of heavy floods is passed and the water level 
approaches normal. 



8 STOKAGE AND GERMINATION OF WILD RICE SEED. 

In sowing the seed considerable care must be exercised in selecting 
a suitable place, securing the proper depth of water, etc. Good 
results can be expected if the seed is sown in from 1 to 3 feet of water 
which is not too stagnant or too swiftly moving, with a thick layer of 
soft mud underneath. 01 It is useless to sow wild rice seed on a gravelly 
bottom or in water where the seed will be constantly disturbed by 
strong currents. 

Previous to this time, save in a few reported cases, the seed which 
was allowed to dry during the winter and was sown the following- 
spring gave only negative results. It is now definitely known that 
wild rice, if properly handled, can be stored during the winter without 
impairing the quality of germination to any appreciable degree, and 
that it can be sown the following spring or summer with good success. 

DIRECTIONS FOE, STORING THE SEED. 

The vitality of wild rice seed is preserved almost perfectly if kept 
wet in cold storage — Nature's method of preservation. This method 
of storage implies that the seed has been properly harvested and cared 
for up to the time of storage. The seed should be gathered as soon 
as mature, put loosely into sacks (preferably burlap), and sent at once 
to the cold-storage rooms. If the wild rice fields are some distance 
from the cold-storage plant the sacks of seed should be sent by express, 
and unless prompt delivery can be guaranteed it is not advisable to 
send by freight even for comparatively short distances. It is very 
important that the period between the time of harvesting and the 
time when the seed is put into cold storage be as short as possible. 
If this time is prolonged to such an extent as to admit of much fer- 
mentation or to allow the seed near the outside of the bags to become 
dry during transit, its vitalit}" will be greatly lowered. 

It is not practicable to give any definite length of time which ma} 7 
elapse between harvesting and storing, inasmuch as the temperature, 
humidity, and general weather conditions, as well as the methods of 
handling the seed, must be taken into consideration. Let it suffice to 
say, however, that the vitality of the seed will be the stronger the 
sooner it is put into cold storage after harvesting. 

As soon as the seed is received at the cold-storage plant, while it is 
still fresh and before fermentation has taken place, it should be put 
into buckets, open barrels, or vats, covered with fresh water, and 
placed at once in cold storage. If there is present a considerable 
quantity of light immature seed or straw, broken sticks, etc., it will 
be profitable to separate this from the good seed b}- floating in water 

a Wild Rice: Its Uses and Propagation. Bulletin No. 50, Bureau of Plant Industry, 
United States Department of Agriculture, 1903. 



STORAGE EXPERIMENTS. 9 

preparatory to storing. The storage room should be maintained at 
a temperature just above freezing— what the storage men usually 

designate as the "chill room." 

When taken from cold storage in the spring the seed must not he 
allowed to dry out before planting, as a few days' diving will destroy 
every embryo. 

Seed which was stored under the foregoing conditions from October 
19, 1903, to November 15, 1901, 393 days, germinated from 80 to 88 
per cent. Another lot of seed, which was stored on October 6, 1904, 
and tested for vitality on April IT, 1905, germinated 79.8 per cent. 

Plate I shows the luxuriant growth made by the seed which was kept 
wet and stored at a temperature of 32° to 31° F. for 393 days. 

DETAILED CONDITIONS AND RESULTS OF STORAGE EXPERI- 
MENTS. 

The foregoing conclusions are based on the results obtained from 
two series of experiments, as follows: 

In October, 1903, a box of wild rice seed was received from Ontario. 
Canada. This seed, as soon as gathered, was loosely packed in moist 
sphagnum and sent by express to the Seed Laboratoiy of the United 
States Department of Agriculture. After a few days, while it was 
yet moist and before any fermentation had taken place, the seed was 
divided into four lots for special treatment, as follows: 

(1) Seed submerged in water and placed in cold storage at a temper- 
ature of 32° to 34° F. 

(2) Seed submerged in water and placed in cold storage at a temper- 
ature of 12° F. The seed was soon embedded in a solid mass of ice 
and remained so until samples were taken for test. 

(3) Seed, without the addition of water, put into cloth bags and kept 
in cold storage at a temperature of 32° to 31° F. 

(1) Seed, without the addition of water, put into cloth bags and kept 
in cold storage at a temperature of 12° F. 

In October, 1901, a second consignment of seed was received from 
Minnesota, and the following additional storage experiments were 
made b}^ Mr. C. S. Scofield, of the Bureau of Plant Industry. 

(5) Seed submerged in water and placed in cold storage at a temper- 
ature of 32° to 31° F., as in No. 1. 

(6) Seed submerged in water and placed in cold storage at a temper- 
ature of 12° F., as in No. 2. 

(7) Seed submerged in water in a galvanized-iron bucket and stored 
on the roof of the laboratoiy building. The water was changed daily 
when not frozen. 



10 STORAGE AND GERMINATION OF WILD RICE SEED. 

(8) Seed submerged in water in a galvanized-iron bucket and stored 
on the roof of the laboratory building, as in No. 7. In this case the 
water was not changed save to replace the loss due to evaporation. 

(9) The conditions for No. 9 were the same as those for No. 8, 
except that air was forced into the water daily when not frozen solid. 

Samples of seed were taken from the different lots and tested for 
vitality at irregular intervals throughout the time of storage, which, 
in the former series, extended over a period approximately thirteen 
months and in the latter series over a period of little more than six 
months. 

Experiments Nos. 1 and 5. — The seed which was submerged in water 
and stored in the "chill room" showed no deterioration in vitality. 
The results of the linai tests gave a germination varying from 79.8 to 
88 per cent. This is practically Nature's method of preserving the 
vitalhVy of the seed during the winter. 

Experiments Nos. % and 6. — The seed which was submerged in 
water and stored at a temperature of 12° F. was all killed before the 
spring following the date of storage. Soon after being placed in stor- 
age the water was frozen solid and the seeds were embedded in a mass 
of ice, in which condition they remained throughout the experiment, 
a portion being cut out from time to time for germination tests. The 
complete loss of vitality in these two lots of seedis attributed not to 
the freezing directly, but to the thorough desiccation as a result of 
the continuous low temperature. 

Experiments Nos. 3 and 4- — The samples of seed which were stored 
in cloth bags at the temperatures of 32° to 34° F. and of 12° F. had, 
for all economic purposes, entirely lost their vitality. The average 
percentage of germination, as shown by the 37 tests made from each 
of the two lots, was less than five-tenths of 1 per cent. 

Experiment No. 7. — The seed which was submerged in water and 
stored on the roof of the laboratory building, the water being changed 
daily, showed a good percentage of germination when the last vitality 
tests were made. If only a small quantity of seed is desired for the 
spring planting and cold storage can not be readily secured, good 
results may be obtained by this treatment; but it is much less certain 
and probabh T more expensive than keeping the seed in cold storage, 
and for this reason is not recommended. The success of this method 
will likewise depend largely on the temperature of the water. 

Experiments Nos. 8 and 9. — On April 22, 1905, samples taken from 
each of these two lots of seed showed a marked deterioration in vitality. 
Thoroughly mixed samples from No. 8 showed a vitality of only 58 
per cent, while No. 9 had deteriorated to 11.3 per cent. 



METHODS OF MAKING GERMINATION TESTS. 11 

PACKING FOR TRANSPORTATION. 

Too much care can not be given to the matter of packing' the Beed 
for transportation, for unless the packing- is properly done the vitality 
of the seed will be destroyed during transit. What is here said applies 
to fresh seed which is to be sown in the autumn, as well as to seed 
which has been kept in cold storage during the winter. It must not 
be forgotten, however, that the vitalit}- of cold-storage seed is more 
quickly destroyed on drying than that of fresh seed. 

For transportation the seed should be carefully packed, with moist 
sphagnum, cocoanut fiber, or tine excelsior, in a loosely slatted box. 
If the time of transportation does not exceed five or six days no spe- 
cial precautions need be taken as to the temperature. During the 
period of transportation it is quite probable that some of the seed will 
germinate, but if sown at once growth will not be retarded and the 
roots will soon penetrate the soil and anchor the young plants. 

If the time of transportation is necessarily long, it is recommended, 
if the best results are desired, that some provision be made for a 
reduced temperature. The nearer the temperature approaches that of 
freezing the better. It has been demonstrated, however, that a fair 
percentage of seed will remain germinable for a considerable time if 
packed as above described. 

On October 10, 1904, Mr. C. S. Scofield sent a small quantity of 
wild rice, packed in moist sphagnum moss in a well-ventilated box, to 
Doctor De Vries, of Amsterdam, Holland. On October 11 or 15 this 
box was placed in cold storage on the steamer in New York Harbor. 
The box of seed was received b}^ Doctor De Vries in good condition on 
November 2, twenty-one days after the seed was packed for shipment. 

METHODS OF MAKING GERMINATION TESTS. 

The samples were tested (1) between folds of blotting paper — our 
regular method for testing the germination of most seeds — and (2) in 
water, Nature's method of sowing wild rice seed. The latter method 
gave much better results and was the one finally adopted for the 
laboratory tests. The seed should be covered with water, the water 
in the dishes to be changed daily. 

Plate I shows the importance of making the germination tests in 
water, as described in the foregoing paragraph. The seed was covered 
with water and placed in a germinating chamber maintained at an 
alternating temperature of 20° C. (68° F.) for eighteen hours, and 
30° C. (84° F.) for six hours, until the majority of the seeds had 
germinated. At this stage the dish containing the seeds was trans- 
ferred to the worktable, which was exposed to the temperature of the 
laboratory — approximately that of a living-room. The water in the 



12 STORAGE AND GERMINATION OF WILD RICE SEED. 

dish was changed daily during- the period of germination, and water 
was afterwards added at irregular intervals to replace the loss by 
evaporation. 

Plate II shows somewhat in detail the different stages in the germina- 
tion of wild rice seeds. The seeds and seedlings are shown in natural 
size. In I and c the first sheath has just burst through the seed coats, 
taking a position at right angles to the seed proper. The lateral roots 
begin to emerge when the first sheath leaf has attained a length of £ to 
li inches. From this time growth continues rapidly, and by the time 
the seedlings are 2 or 3 inches long the root system is very well 
developed (f and g). At this stage under favorable conditions the 
plants have a good hold in the soil and will not be washed away by an 
ordinary freshet. The relative position of the actively growing 
seedling is always at right angles to that of the old seed, as shown in 
/and g. 

EFFECT OF TEMPERATURE ON GERMINATION. 

Germination tests were made at constant and alternating tempera- 
tures, ranging from 15 : to 35° C. (59° to 95° F.). While no effort 
was made to show the minimum and maximum temperatures of ger- 
mination, the percentage was somewhat reduced at a constant tempera- 
ture of 35° C, and the maximum is not much above that. All of the 
other temperatures gave good results. The lower temperatures, how- 
ever, were slightly more favorable than the higher. These facts are 
valuable to show that the wild rice plant can thrive in either warm or 
cold water, but better, perhaps, in northern than in southern latitudes. 

SUMMARY. 

(1) Under no circumstances should wild rice seed which is intended 
for planting be allowed to dry. Dried seed will germinate but rarely 
and should never be sown. 

(2) Wild rice seed can be stored without deterioration if it is gath- 
ered as soon as matured, put into barrels or tanks, covered with fresh 
water, and, before fermentation has set in, stored at a temperature of 
32-31° F. Seed treated in this way germinated as high as 88 per cent 
after being in storage 393 days. Fresh seed seldom germinates better, 
and usually not so well. 

(3) After the seed is taken from cold storage it should not be 
allowed to dry. The vitality of cold-storage seed is destined on 
drying even more quickly than that of fresh seed. 

(1) For transportation the seed should be packed in moist sphagnum, 
cocoanut fiber, or fine excelsior. If not more than five or six days 
are required for transit, no special precautions need be taken for con- 
trolling the temperature; but if the time for transportation exceeds 



SUMMARY. 13 

six days, provision should be made for a temperature sufficiently low 
to prevent marked fermentation. A temperature approximately 
freezing- will give the most .satisfactory results. 

(5) Wild rice can be sown either in the autumn or in the spring. 
Spring sowing is preferable, thus avoiding the danger of having the 
seed eaten or destroyed by wild ducks or other animals during the fall 
or winter, or of its being buried or washed away by the heavy floods 
of late winter or early spring. 

(6) Wild rice should be sown in the spring in from 1 to 3 feet of 
water which is neither too stagnant nor too swiftly moving, as soon as 
the danger of heavy Hoods is passed. 

(7) Wild rice is of the greatest importance as a food for wild water- 
fowl, likewise a delicious breakfast food for man, and the area in which 
it is extensively grown should be extended. It will grow luxuriantly 
in either warm or cold water; furthermore, it can be grown .success- 
fully in water which is slightly salty to the taste. 

(8) In determining the vitality of any sample of wild rice seed the 
germination tests should be made in water — the condition under which 
the self-sown seed germinates. 

(9) The seed will germinate well at temperatures ranging from 
15° to 30° C. The maximum temperature of germination is above 
35° C. (95° F.), but better results are obtained at lower temperatures. 



PLATES. 



15 



DESCRIPTION OF PLATES. 

Plate I. Wild rice growing in water. This seed was submerged at a temperature of 
32-34° F. for approximately thirteen months. In making the germination test 
the seed was covered with water and placed in a germinating chamber main- 
tained at a temperature of 20° C. (68° F. ) for eighteen hours, and at 30° C. 
(86° F. ) for six hours. After the majority of the seeds had germinated the dish 
was transferred to the worktable of the Seed Laboratory. 

Plate II. Progressive stages in the development of wild rice seedlings; /and g, seed- 
lings showing the relative position of the growing seedlings and the parent seed, 
which take a position at right angles to each other when grown normally in 
water. (Natural size. ) 
16 



o 



90, Pt. I, Bureau of Plant Industry, U. S. Dept. of Agncultur 



Plate I. 




Wild Rice Growing in Water after being Kept Wet in Cold Storage at a Tem- 
perature of 32-34° F., from October 19, 1903, to November 15, 1904. 



Bui. 90, Pt. I, Bureau of Plant Industry, U. S. Dept. of Agricult"rp. 



Plate II. 




Stages of Germination of Wild Rice, Showing the Development of the 
Root System and the Relative Position of the Seedling and the 
Parent Seed. Natural Size. 



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